The effect of glyphosate, its metabolites and impurities on erythrocyte acetylcholinesterase activity.

Glyphosate [N-(phosphonomethyl)glycine] is used all over the world to protect agricultural and horticultural crops. According to initial reports, glyphosate has been considered to be safe for humans and animals; nevertheless, recent investigations had proven its toxicity. Extensive use of glyphosate and the conviction of its low toxicity leads to a situation in which it is used in excessive amounts in agriculture. That is why, we have investigated the effect of the most commonly used pesticide: glyphosate, its metabolites and impurities on acetylcholinesterase (AChE) activity (in vitro) in human erythrocytes, which is biochemically similar to acetylcholinesterase present in neural synapses. The analysis of noxious effects of metabolites and impurities of pesticides seems to be very important to evaluate toxicological risk that is associated with the effect of pesticide formulations (requirement of the EU regulations 1107/200/EC). The erythrocytes were incubated with xenobiotics at concentrations range from 0.01 to 5 mM for 1 and 4 h. Statistically significant decrease in AChE activity (about 20%) was observed only at high concentrations of the compounds (0.25-5 mM), which enter body only as a result of acute poisoning. There were no statistically significant differences in the effect of the investigated compounds, while the changes caused by them were similar after 1 and 4 h incubation. The investigated metabolites and impurities did not cause stronger changes in AChE activity than glyphosate itself. It may be concluded that the compounds studied (used in the concentrations that are usually determined in the environment) do not disturb function of human erythrocyte acetylcholinesterase.